Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!srhqla!demott!kdq
From: kdq@demott.com (Kevin D. Quitt)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: null modem cable
Message-ID: <1991Jan21.165850.10401@demott.com>
Date: 21 Jan 91 16:58:50 GMT
References: <2582@s5.Morgan.COM>
Distribution: usa
Organization: DeMott Electronics Co., Van Nuys CA
Lines: 56

In article <2582@s5.Morgan.COM> joec@Morgan.COM (Joe Collins) writes:
>Anyone know how to make an null modem cable or should

    More than you even wanted to know about RS232 cables:

DB9	RS232
Pin	Signal
 1	CD	Carrier Detect
 2	RxD	Received Data
 3	TxD	Transmitted Data
 4	DTR	Data Terminal Ready
 5	SGnd	Signal Ground
 6	DSR	Data Set Ready
 7	RTS	Request to Send
 8	CTS	Clear To Send
 9	RI	Ring Indicator

DB25	RS232
Pin	Signal
 1	CGnd	Case Ground
 2	TxD
 3	RxD
 4	RTS
 5	CTS
 6	DSR
 7	SGnd
 8	CD
9-19	Not usually used
20	DTR
21-25	Not usually used

			  RS232C Null-Modem Cable

		DB9	DB25			DB25	DB9
		Pin	Pin			Pin	Pin
		 1	 8	 CD	DTR	20	 4
		 2	 3	 RxD	TxD	 2	 3
		 3	 2	 TxD	RxD	 3	 2
		 4	20	 DTR	DSR	 6	 6
		 4	20	 DTR	CD	 8	 1
		 5	 7	 SGnd	SGnd	 7	 5
		 6	 6	 DSR	DTR	20	 4
		 7	 4	 RTS	CTS	 5	 8
		 8	 5	 CTS	RTS	 4	 7
		 9		 RI

		1-6	6-8			6-8	1-6	<- Jumpers

Note:	If for some reason, you cannot jumper DSR to CD, connect
	DSR to the opposite DTR, and connect CD straight across
	(if possible).
-- 
 _
Kevin D. Quitt         demott!kdq   kdq@demott.com
DeMott Electronics Co. 14707 Keswick St.   Van Nuys, CA 91405-1266
VOICE (818) 988-4975   FAX (818) 997-1190  MODEM (818) 997-4496 PEP last